Business Pro - Invoice Improvement

I like the idea of being able to send my invoices directly from the business account, however it’s very annoying that I’m not able to add custom notes to the item that I invoice. For example; if I am contracted to work as a trainer and it comes to invoicing the training company, there is no option to personalise each item. For example; if I am invoicing delivery of training session one with different clients, I have to list each of these as their own item (session 1 - client a, session 1 - client b, etc). There should be the option to list it all as one item (session 1 listed as item and below that in notes I can list client a, client b).
Without this I have to create a new item for every single invoice I create which is very tedious. This is something that most if not all invoicing apps already offer and I thought it would be a feature of Monzo invoices but it’s not which is disappointing and honestly deters me from wanting to use it. Is there any way to add this?

I used monzo business for a few years. Now switched to mettle with freeagent for free, and have to say for a sole trader its absolutely perfect - unbeatable imo.